Antiseptic solutions and applicators

ABSTRACT

An antiseptic solution comprising a pH-dependent antimicrobial agent, the pH-dependent antimicrobial agent having an operative pH range, wherein the solution has a pH on storage that is lower than the operative pH range. Applicators for applying the antiseptic solution and methods of using the antiseptic solution and applicators are also provided.

BACKGROUND Field

The present disclosure relates to antiseptic solutions and applicators,and methods of use thereof. More particularly, the present disclosurerelates to an antiseptic solution comprising a pH-dependentantimicrobial agent having an operative pH range, wherein the solutionhas a pH on storage that is lower than the operative pH range, andapplicators for applying the antiseptic solution to a surface.

Description of Related Art

Antiseptic solutions containing antimicrobial agents that may beapplied, for example, to a patient's skin to kill bacteria prior toperforming a medical procedure are known in the art. However, inexisting antiseptic solutions, antimicrobial agents often degrade duringmanufacturing (e.g., sterilization) and/or over time, particularly insolutions that contain water. In many cases, the degradation rate of theantimicrobial agent is impacted by the pH of the antiseptic solution. Inaddition, the microbiological activity of the antimicrobial agent canalso be impacted by the pH of the solution. Often, there is not a singlepH value or pH range which allows both acceptable chemical stability andmicrobiological activity of the antimicrobial agent.

As such, when using applicators to apply antiseptic solutions known inthe prior art, it may be difficult to provide both acceptable chemicalstability on storage and microbiological activity upon application. Forexample, the pH necessary for acceptable chemical stability of anantiseptic solution may be different than the pH necessary foracceptable microbiological activity. Thus, there is a need in the artfor an antiseptic solution and applicator that allows both acceptablechemical stability on storage and microbiological activity upon use ofan antiseptic solution.

SUMMARY

In accordance with aspects of the present invention, an antiseptic mayinclude a solution comprising a pH-dependent antimicrobial agent, thepH-dependent antimicrobial agent having an operative pH range, whereinthe solution has a pH on storage that is lower than the operative pHrange. According to some aspects, the solution may comprise apH-lowering agent. According to some aspects, the solution may comprisea second pH upon activation, wherein the first pH is lower than theoperative pH range, and the second pH is within the operative pH range.

In accordance to other aspects, an antiseptic solution may be providedin an applicator which may include a body, an internal chamber forcontaining the antiseptic solution, and an application member. Accordingto some aspects, the applicator may further comprise an ampoule receivedin the internal chamber, wherein the antiseptic solution is containedwithin the ampoule. According to some aspects, the applicator may alsocomprise a pledget positioned between the application member andinternal chamber, wherein the pledget may help control the rate liquidflows from the body, provide dye to the liquid, and/or prevent shards ofglass from pushing through application member during use of theapplicator. According to some aspects, the pledget and/or applicationmember may be provided with an interaction agent so that when antisepticsolution passes through the pledget and/or application member, one ormore components of the antiseptic solution interact with the interactionagent.

It will become readily apparent to those skilled in the art from thefollowing detailed description, wherein it is shown and described onlyexemplary configurations of the antiseptic solution and applicator. Aswill be realized, the invention includes other and different aspects ofan antiseptic solution and applicator and the various details presentedthroughout this disclosure are capable of modification in various otherrespects, all without departing from the spirit and scope of theinvention. Accordingly, the drawings and the detailed description are tobe regarded as illustrative in nature and not as restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side cutaway view of an antiseptic applicator having apledget in accordance with certain aspects of the present invention.

FIG. 2 is a perspective view of an antiseptic applicator in accordancewith certain aspects of the present invention.

FIG. 3 is a perspective view of the head portion of the antisepticapplicator of FIG. 2.

FIG. 4 shows pH vs. concentration of total related substances insolutions comprising gluconic acid as a pH-lowering agent, as describedin Example 2.

FIG. 5 shows pH vs. concentration of total related substances insolutions comprising acetic acid as a pH-lowering agent, as described inExample 2.

FIG. 6 shows pH vs. concentration of total related substances insolutions comprising citric acid as a pH-lowering agent, as described inExample 2.

FIG. 7 shows the concentration of chlorhexidine gluconate in differentantiseptic solution fractions using Dowex® 66 free base anion exchangeresin as a scavenging agent, as described in Example 4.

FIG. 8 shows the concentration of chlorhexidine gluconate in differentantiseptic solution fractions using AMBERLITE™ IRA96 anion exchangeresin as a scavenging agent, as described in Example 4.

FIG. 9 shows the concentration of chlorhexidine gluconate in differentantiseptic solution fractions using Amberlyst® A21 free base anionexchange resin as a scavenging agent, as described in Example 4.

FIG. 10 shows the efficacy against Staphylococcus aureus ATCC 29213 indifferent antiseptic solution fractions, as described in Example 5.

DETAILED DESCRIPTION

In accordance with aspects of the present invention, an antiseptic mayinclude a solution comprising a pH-dependent antimicrobial agent havingan operative pH range.

As used herein, the term “about” means within ±10%, preferably ±5%, morepreferably ±1% of the given value. As used herein, the term “stable”with respect to a solution means that there is no discernibleprecipitation, particulates, haziness, or cloudiness present in thesolution, when viewed by the unaided human eye (i.e., that all of thecomponents in the solution remain solubilized). As used herein, the term“unstable” with respect to a solution means that there is a discernibleprecipitation, particulates, haziness, and cloudiness present in thesolution, when viewed by the unaided human eye (i.e., at least one ofthe components of the solution has become at least partiallyinsolubilized). In other words, a “stable” solution appears clear to thenaked eye while an unstable solution has at least some visibleprecipitation, particulate, haziness, or cloudiness.

As used herein, the term “pH-dependent antimicrobial agent” refers to anantimicrobial agent whose antimicrobial activity is affected by pH.According to some aspects, suitable pH-dependent antimicrobial agentsinclude biguanides (e.g., chlorhexidine salts). According to somepreferred aspects, the pH-dependent antimicrobial agent may comprisechlorhexidine and/or one or more salts thereof. For example, accordingto some aspects, the pH-dependent antimicrobial agent may be selectedfrom the group consisting of chlorhexidine gluconate, chlorhexidineacetate, chlorhexidine, chlorhexidine hydrochloride, and any combinationthereof.

Examples of biguanides/biguanide derivatives other thanchlorhexidine/chlorhexidine salts include but are not limited toalexidine, alexidine salts, polyhexamide, polyhexamide salts,polyaminopropyl biguanide, polyaminopropyl biguanide salts, and otheralkyl biguanides. As used herein, the term “derivative” refers to a) achemical substance that is related structurally to a first chemicalsubstance and derivable from it; b) a compound that is formed from asimilar first compound or a compound that can be imagined to arise fromanother first compound, if one atom of the first compound is replacedwith another atom or group of atoms; c) a compound derived or obtainedfrom a parent compound and containing essential elements of the parentcompound; or d) a chemical compound that may be produced from firstcompound of similar structure in one or more steps.

According to some aspects, the concentration of the pH-dependentantimicrobial agent in the antiseptic solution may vary depending on thespecific pH-dependent antimicrobial species used or the desiredantimicrobial effect. For example, according to some aspects, theconcentration of the pH-dependent antimicrobial agent in the solutionmay be from about 0.01% to about 20% w/v, preferably from about 0.01% toabout 10% w/v, even more preferably from about 0.01% to about 5%, evenmore preferably from about 0.5% to about 4%, and most preferably fromabout 1% to about 3% w/v. According to some aspects, the pH-dependentantimicrobial agent concentration in the solution may be from about 0.5%to about 2% w/v. According to some aspects, the pH-dependentantimicrobial agent concentration in the solution may be about 2% w/v.

According to some aspects, the pH-dependent antimicrobial agent may beprovided in a solution comprising a solvent. According to some aspects,the solvent comprises an organic component. In some embodiments, thepH-dependent antimicrobial agent may be provided in a solutioncomprising at least one solvent comprising water and/or an alcohol,preferably isopropyl alcohol, ethyl alcohol, n-propyl alcohol, and anycombination thereof.

According to some aspects, the concentration of the solvent in thesolution may be from about 50% to about 99.99% v/v, preferably about 55%to about 90% v/v, more preferably about 60% to about 85% v/v, even morepreferably about 65% to 75% v/v. According to some aspects, the solventconcentration in the solution may be about 70% v/v.

According to some aspects, the antiseptic solution may comprise 2% w/vchlorhexidine gluconate in 70% v/v isopropyl alcohol.

According to some aspects, the antiseptic solution may be aqueous. Thatis, the solvent of the solution is primarily water. As used herein, theterm “aqueous” means at least about 50% v/v water, more preferably atleast about 60% v/v water, more preferably at least about 70% v/v water,more preferably at least about 80% v/v water, more preferably at leastabout 90% v/v water, more preferably at least about 95% v/v, up to 100%v/v water. According to some aspects, when the solution is less than100% v/v water, the remaining volume may include one or more additionalsolvents, for example, alcoholic solvents.

According to some aspects, the pH-dependent antimicrobial agent has anoperative pH range. As used herein, the term “operative pH range” refersto the pH range of an antiseptic solution containing the pH-dependentantimicrobial agent where the pH-dependent antimicrobial agent exhibitsacceptable microbiological activity. According to some aspects, theoperative pH range may be the pH range of an antiseptic solutioncontaining the pH-dependent antimicrobial agent where the pH-dependentantimicrobial agent kills at least 70% of the targeted microorganisms ona surface to which the antiseptic solution has been applied, preferablyat least 75%, more preferably at least 80%, even more preferably atleast 85%, even more preferably at least 90%, even more preferably atleast 95%, and most preferably 100%.

According to some aspects, the operative pH range may be the pH range ofan antiseptic solution containing the pH-dependent antimicrobial agentwhere the pH-dependent antimicrobial shows at least a 2 log reduction oftargeted microorganisms on a surface to which the antiseptic solutionhas been applied, preferably at least a 3 log reduction, more preferablyat least a 3.5 log reduction, and most preferably at least a 4 logreduction.

According to some aspects, the operative pH range may be a pH of atleast 5.0, preferably at least 5.1, more preferably at least 5.2, evenmore preferably at least 5.3, even more preferably at least 5.4, andmost preferably at least 5.5.

According to some aspects, the antiseptic solution has a pH on storagethat is lower than the operative pH range. As used herein, the term“storage” refers to the storing of the antiseptic solution up to itspoint of use, or up to the point of activation, as described herein.According to some aspects, storage may refer to the period of time whenthe antiseptic solution is contained within a container. For example,according to some aspects, storage may refer to the period of time whenthe antiseptic solution is contained within the ampoule of anapplicator. According to some aspects, the ampoule may be hermeticallysealed. According to some aspects, the ampoule may comprise a materialthat minimizes the loss of gaseous components and/or prevents theantiseptic solution therein from contacting a surrounding environment.

According to some aspects, storage may require certain environmentalconditions. For example, according to some aspects, storage may requirecertain temperature and/or relative humidity (RH) conditions. Accordingto some aspects, storage may refer to environmental conditions of 25°C.±2° C. and 60% RH±5% RH. According to some aspects, storage may referto environmental conditions of 30° C.±2° C. and 65% RH±5% RH. In someembodiments, storage may also or alternatively refer to conditionsnecessary for manufacture (e.g., elevated temperatures necessary forsterilization).

According to some aspects, the antiseptic solution has a pH on storagethat is at least 0.1 pH units lower than the operative pH range,preferably at least 0.2 pH units lower than the operative pH range, morepreferably at least 0.3 pH units lower than the operative pH range, evenmore preferably at least 0.4 pH units lower than the operative pH range,even more preferably at least 0.5 pH units lower than the operative pHrange, even more preferably at least 0.6 pH units lower than theoperative pH range, even more preferably at least 0.7 pH units lowerthan the operative pH range, even more preferably at least 0.8 pH unitslower than the operative pH range, even more preferably at least 0.9 pHunits lower than the operative pH range, and most preferably at least 1pH unit lower than the operative pH range. According to some aspects,the antiseptic solution may have a pH on storage that is no more than5.0.

According to some aspects, the antiseptic solution may have a pH onstorage such that the rate of degradant formation on storage is reduced.As used herein, the term “degradant” refers to an undesired substance ina composition. In some embodiments, degradants may be formed viadegradation of one or more components of the antiseptic solution. Insome embodiments, degradants may be formed via degradation of thepH-dependent antimicrobial agent.

According to some aspects, the antiseptic solution may have a pH onstorage such that the rate of degradant formation on storage is lowerthan the rate of degradant formation on storage of an identical solutionexcept without having a pH-lowering agent, as described herein. Forexample, according to some aspects, the antiseptic solution may have apH on storage such that the pH-dependent antimicrobial agent degrades ata slower rate than it would degrade in a solution with a higher pH.According to some aspects, the antiseptic solution may have a pH onstorage such that the pH-dependent antimicrobial agent degrades at aslower rate than it would degrade in a solution with a pH within theoperative pH range.

According to some aspects, the antiseptic solution may have a pH onstorage such that the antiseptic solution is stable for a certain periodof shelf life. According to some aspects, the antiseptic solution mayhave a pH on storage such that the antiseptic solution has a lowerconcentration of degradants after a certain period of shelf life than anidentical solution except without having a pH-lowering agent, asdescribed herein. In some embodiments, the antiseptic solution may havea pH on storage such that the antiseptic solution has a lowerconcentration of degradants after a certain period of shelf life than asimilar antiseptic solution with a pH within the operative pH range.

According to some aspects, the period of shelf life of the antisepticsolution may be at least 1 month, preferably at least 2 months, morepreferably at least 3 months, more preferably at least 4 months, morepreferably at least 5 months, more preferably at least 6 months, morepreferably at least 7 months, more preferably at least 8 months, morepreferably at least 9 months, more preferably at least 10 months, morepreferably at least 11 months, more at least 12 months, preferably atleast 13 months, more preferably at least 14 months, more preferably atleast 15 months, more preferably 1 at least 6 months, more preferably atleast 17 months, more preferably at least 18 months, more preferably atleast 19 months, more preferably at least 20 months, more preferably atleast 21 months, more preferably at least 22 months, more preferably atleast 23 months, more preferably at least 24 months, more preferably atleast 25 months, more preferably at least 26 months, more preferably atleast 27 months, more preferably at least 28 months, more preferably atleast 29 months, more preferably at least 30 months, more preferably atleast 31 months, more preferably at least 32 months, more preferably atleast 33 months, more preferably at least 34 months, more preferably atleast 35 months, and most preferably at least 36 months.

According to some aspects, the solution may comprise a pH-loweringagent. As used herein, the term “pH-lowering agent” refers to acomponent of the antiseptic solution selected to lower the solution'spH. In some embodiments, the pH-lowering agent may be present in theantiseptic solution such that the solution has a pH on storage asdescribed herein. According to some aspects, the presence of thepH-lowering agent lowers the pH of the antiseptic solution from theoperative pH range to the pH on storage. In other words, according tosome aspects, an antiseptic solution without the pH-lowering agent mayhave a pH within the operative pH range, while the same antisepticsolution containing the pH-lowering agent may have a pH on storage asdescribed herein.

According to some aspects, the pH-lowering agent may comprise a compoundwhich reversibly reacts with one or more components of the antisepticsolution in order to lower the pH of the solution. An example of apH-lowering agent which reversibly reacts with components of theantiseptic solution includes, but is not limited to, carbon dioxide.

According to some aspects, the pH-lowering agent may comprise a gas. Forexample, according to some aspects, the pH-lowering agent may comprise agas which has been bubbled through the antiseptic solution prior to theantiseptic solution being contained within a sealed container (e.g., anampoule of an applicator), such that the antiseptic solution comprises aconcentration of the gas above the normal atmospheric concentration. Forexample, according to some aspects, the pH-lowering agent may comprisegaseous carbon dioxide. According to some aspects, the gaseouspH-lowering agent may be bubbled through the chilled antiseptic solution(e.g., chilled at approximately 2-8° C.). Gaseous carbon dioxide, forexample, may then reversibly react with water in the antiseptic solutionto reversibly form carbonic acid, thereby resulting in a decrease of thepH of the antiseptic solution.

According to some aspects, the pH-lowering agent may comprise an acid.As used herein, the term “acid” refers to a compound that acts as aproton (hydrogen ion) donor. According to some aspects, the pH-loweringagent may comprise one or more of, but not limited to, acetic acid,adipic acid, ascorbic acid, citric acid, hydrochloric acid, gluconicacid, lactic acid, malic acid, phosphoric acid, pyrophosphoric acid,succinic acid, sulfuric acid, tartaric acid, and/or trifluoroaceticacid.

According to some aspects, the solution may have second pH afterstorage, wherein the second pH is within the operative pH range.According to some aspects, the solution may have a second pH uponactivation. As used herein, the term “activation” refers to a certainevent immediately or shortly after storage which elicits a change in theantiseptic solution's pH.

In some embodiments, activation comprises contacting the antisepticsolution with a surrounding atmosphere, for example, by opening a sealedcontainer in which the solution has been stored (e.g., an internalchamber or an ampoule within an internal chamber of an applicator)and/or releasing the solution from the container. According to someaspects, contacting the antiseptic solution with a surroundingatmosphere allows all or a portion of a gaseous pH-lowering agent to bereleased from the solution, such that the gaseous pH-lowering agent isno longer present or present at a reduced concentration in the solution,and thus no longer capable of reversibly reacting with componentsthereof. As a result, without the presence of the pH-lowering agent, thepH of the antiseptic solution will increase.

For example, in one embodiment, an antiseptic solution comprisinggaseous carbon dioxide may have a pH on storage when contained within anampoule of an applicator. In this example, the ampoule may becomefractured, crushed, or otherwise opened, thereby releasing theantiseptic solution therefrom and allowing the solution to contact asurrounding atmosphere. Upon the solution's release from the ampoule,gaseous carbon dioxide may be released from the solution and into thesurrounding atmosphere. In this example, as the concentration of carbondioxide in the solution decreases, the carbonic acid in the solutionwill simultaneously convert into carbon dioxide and water, and theformed carbon dioxide will subsequently also be released from thesolution. In this way, the pH of the solution will increase as theconcentration of carbonic acid in the solution decreases.

According to some aspects, the solution will have a second pHimmediately upon activation. According to some aspects, the solutionwill have a second pH shortly following activation. For example, in someembodiments, the solution will have a second pH within about 120 secondsafter activation, preferably within about 90 seconds after activation,more preferably within about 60 second after activation, and mostpreferably within about 30 second after activation. According someaspects, the solution will have a second pH when it is applied to asurface.

In some embodiments, activation comprises contacting the antisepticsolution with an interaction agent. As used herein, the term“interaction agent” refers to a component that interacts with apH-lowering agent in an antiseptic solution to increase the pH of theantiseptic solution.

According to some aspects, the interaction agent may comprise aneutralizing agent. As used herein, the term “neutralizing agent” refersto a component that chemically reacts with the pH-lowering agent in anantiseptic solution such that the pH-lowering agent is at leastpartially converted to a component that does not lower the pH of theantiseptic solution. According to some aspects, the neutralizing agentmay react with an acidic pH-lowering agent. Example neutralizing agentsinclude but are not limited to sodium bicarbonate, sodium carbonate,carbonate (e.g., using CO₂), and potassium carbonate. According to someaspects, the neutralizing agent may be the same as or comprise ascavenging agent, as described herein. According to some aspects, thereaction between the neutralizing agent and the pH-lowering agent mayresult in the formation of salt compounds which do not impact themicrobiological efficacy of the pH-dependent antimicrobial agent.

According to some aspects, the neutralizing agent may react with all ora portion of the pH-lowering agent in the antiseptic solution. In someembodiments, the neutralizing agent may react with at least 50% of thepH-lowering agent in the antiseptic solution, preferably at least 60%,more preferably at least 70%, even more preferably at least 80%, evenmore preferably at least 90%, and most preferably 100%.

According to some aspects, the interaction agent may comprise ascavenging agent. As used herein, the term “scavenging agent” refers toa component that removes the pH-lowering agent from an antisepticsolution, resulting in an increase in the antiseptic solution's pH.

According to some aspects, the scavenging agent may comprise afunctional group that interacts with (e.g., binds to), preferablyselectively interacts with, the pH-lowering agent. For example, thescavenging agent may comprise an ion exchange resin, e.g., an anionicexchange resin. Examples of suitable scavenging agents include but arenot limited to ion-exchange polymers. Examples of suitable ion-exchangepolymers include but are not limited to Dowex® 66 free base anionexchange resin, AMBERLITE™ IRA96 anion exchange resin, and Amberlyst®A21 free base anion exchange resin, and ScavengePore™ phenethyldiethylamine.

According to some aspects, the scavenging agent may remove all or aportion of the pH-lowering agent in the antiseptic solution. In someembodiments, the scavenging agent may remove at least 50% of thepH-lowering agent in the antiseptic solution, preferably at least 60%,more preferably at least 70%, even more preferably at least 80%, evenmore preferably at least 90%, and most preferably 100%.

In some preferred embodiments, activation may result in minimal or noimpact to the chemical integrity of the pH-dependent antimicrobialagent. According to some aspects, activation may result in a chemicalchange in less than about 10% of the pH-dependent antimicrobial agent.According to some aspects, activation may result in minimal or no impacton the total related substances in the antiseptic solution, and/orresults in little or no formation of any additional impurities in theantiseptic solution that were not present prior to activation. Accordingto some aspects, activation may results in less than about a 10%increase of total related substances as compared to an identicalsolution that has not been activated. According to some aspects,activation may results in less than about a 10% increase of impuritiesas compared to an identical solution that has not been activated.

According to some aspects, the antiseptic solution may be provided in anapplicator configured to apply the antiseptic solution to a surface. Insome embodiments, the surface may be animal skin or human skin.

According to some aspects of the present invention, the applicatorincludes a body, an internal chamber for containing the antisepticsolution, and an application member. According to some aspects, theapplicator may further comprise an ampoule received in the internalchamber, wherein the antiseptic solution is contained within theampoule. According to some aspects, the applicator may also a pledgetpositioned between the application member and internal chamber, whereinthe pledget may help control the rate liquid flows from the body and/orprevent shards of glass from pushing through application member duringuse of the applicator. According to some aspects, the pledget and/orapplication member may be provided with an interaction agent so thatwhen antiseptic solution passes through the pledget and/or into theapplication member, one or more components of the antiseptic solutioninteracts with the interaction agent. That is, according to someembodiments, “activation” may refer to when the antiseptic solutionpasses through the pledget and/or into the application member providedwith the interaction agent.

Some applicators which may be used in accordance with aspects of thepresent invention rely on various means of actuation to release aself-contained reservoir of an antiseptic solution for sterilization ofthe patient's skin. For example, a number of applicators are designedwith a puncturing means. These applicators typically include a head witha spike, for example, and a sealed container or cartridge. A push orscrew motion is employed to axially translate the head toward the sealedcontainer so that the spike may pierce the sealed container andeffectuate the release of the solution contained therein. Some examplesof applicators using a puncturing means include U.S. Pat. Nos.4,415,288; 4,498,796; 5,769,552; 6,488,665; and 7,201,525; and U.S. Pat.Pub. No. 2006/0039742, each incorporated by reference.

Other applicators which may be used in accordance with aspects of thepresent invention rely on breaking an internally situated frangibleampoule through the application of a one-way directional force or alocalized application of pressure. The directional force is typicallyapplied longitudinally to one end of the ampoule by a pushing motiondesigned to force the ampoule to break under a compressive stress,sometimes at a predetermined area of stress concentration.Alternatively, a pressure may be applied to a localized section of theampoule through a squeezing motion designed to crush a section of thefrangible ampoule in order to release the antimicrobial solutioncontained therein. Some examples of applicators using frangible ampoulesin the manner discussed above include U.S. Pat. Nos. 3,757,782;5,288,159; 5,308,180; 5,435,660; 5,445,462; 5,658,084; 5,772,346;5,791,801; 5,927,884; 6,371,675; and U.S. Pat. Nos. 6,916,133,7,182,536, each incorporated by reference.

Other applicators which may be used in accordance with aspects of thepresent invention include other methods of releasing antisepticsolution, such as in U.S. Pat. Nos. 8,708,983; 8,899,859; and 9,265,923;and U.S. Pat. Pub. No. 2013/0251439, each incorporated by reference.

Other related art applicators include those described in U.S. Pat. No.9,119,946, U.S. Pat. Pub. No. 2011/0319842; U.S. application Ser. No.14/595,084, entitled “Antiseptic Applicator,” filed Jan. 12, 2015; andU.S. application Ser. No. 14/566,608, entitled “Antiseptic Applicator,”filed Dec. 10, 2014, each incorporated by reference.

Various aspects of an antiseptic applicator may be illustrated withreference to one or more exemplary embodiments. As used herein, the term“exemplary” means “serving as an example, instance, or illustration,”and should not necessarily be construed as preferred or advantageousover other embodiments of an antiseptic applicator disclosed herein.

FIG. 1 shows an example of an antiseptic applicator 10 which may be usedin accordance with the present invention. Antiseptic applicator 10generally includes a body 12, and an application member 16 secured toflange of body 12 and a lever 26. A frangible ampoule 14 for containingantiseptic solution is received in body 12. One end is closed with cap19. Body 12 includes an internal chamber 22. The wall of the applicatorincludes thinner wall 40. The thickness of the wall of body 12 isreduced around crush area 42. Thin wall 40 makes it easier for crushportion 36 of lever 26 to fracture ampoule 14 when lever 26 isdepressed. Pledget 46 is positioned between application member 16 andampoule 14. Pledget 46 helps control the rate liquid flows from the bodyand/or prevents shards of glass from pushing through application member16 during use of the applicator. Lever 26 includes hinge portion 38,crush portion 36 and handling portion 34 extending from the distal endof lever 26. When the lever 26 is depressed, force is transferred intothe crush portion 36 of the lever 26.

According to some aspects, the pledget 46 may be impregnated orotherwise provided with the interaction agent. The foam applicationmember 16 may comprise a single uniform piece of foam, which mayadditionally or alternatively be impregnated or otherwise provided withthe interaction agent. In this example applicator of FIG. 1, theantiseptic solution is released by actuating the lever 26 with enoughforce for the ampoule 14 to break.

FIGS. 2 and 3 show another example antiseptic applicator 100 that may beused in accordance with aspects of the present invention. As shown inFIGS. 2 and 3, the applicator 100 may comprise a substantially hollowcontainer 102 containing or forming a fluid chamber, a head portion 110coupled to a distal end of the container 102, and an application member104 mounted to the head portion 110. The head portion 110 may include aproximal end, a distal end, and an interior portion defining a fluidchamber. As shown in FIG. 3, a proximal end of the head portion 110 maybe attached to the distal end of the container 102, while the distal endof the head portion 110 may be attached to the application member 104.Thus, the head portion 110 may be disposed between the container 102 andthe application member 104. The applicator 100 may include an actuatingarm 106, that, when depressed releases antiseptic solution stored in thecontainer 102. Various example mechanisms and methods for releasingantiseptic solution from the container into the chamber of the headportion are included in the above-listed related art references, each ofwhich is incorporated by reference herein. It should be understood thatall of the structure shown in FIG. 2 may be substituted with anysuitable structure found in the cited related art applicators. That is,one having ordinary skill in the art may apply the application member104 to any known antiseptic applicator by replacing the applicationmember of the related art antiseptic applicator with the applicationmember 104. For example, the application member 104 may be applied toany of the application members of the above-cited references. A pledgetsimilar to the pledget shown in FIG. 1 may also be included in theantiseptic applicator 100.

The application member 104 may comprise a foam sponge material, forexample, or any suitable material that allows the controlled applicationof the contained solution from the container 102 to a surface externalto the applicator 100. For example, the foam may comprise polyurethanefoam. The foam may be hydrophilic or hydrophobic, depending on theantiseptic solution contained in the container. Suitable foams or othermaterials for the application member 104 may be found in the relatedapplicators. In accordance with aspects of the present invention, theapplication member 104 may be impregnated with the interaction agent. Insome embodiments, the application member 104 may include a first layer112 and a second layer 114, wherein either the first layer 112 or thesecond layer 114 may be impregnated or otherwise provided with theinteraction agent. The first layer and/or second layer may beimpregnated with the interaction agent by spray coating, dipping thefoam into the interaction agent and allowing it to be adsorbed thereon,or mixing the interaction agent into the foam base as the foam isformed, for example. As shown in FIG. 3, the first foam layer 112 may bepositioned or disposed toward the distal end of the head portion 110,and the second foam layer 114 may be disposed away from the distal endof the head portion 110. In other words, the first foam layer may be theportion of the application member that is attached to the head portion,while the second foam layer may be the portion that contacts thepatient's skin during use. Thus, in this arrangement, duringapplication, the antiseptic solution first passes through the first foamlayer and then passes through the second foam layer. The foam materialchosen may be porous with a particular soak rate, for example, or may beprovided with structural features, including slits or apertures, todirect and control the flow rate of the solution through the applicationmember 104. The first and second foam layers may comprise the same ordifferent foam materials. Additionally, the first and second foam layersmay be integral with each other. In other words, the application member104 may be formed from a single piece of foam. When the first and secondfoam layers are formed from separate pieces, the layers may be connectedby a porous adhesive, sonic lamination, or heat lamination, for example.

The container 102 is preferably a self-contained structure, formed of asuitable material, such as a plastic, e.g., a high-density polyethyleneplastic, that is flexible, yet resistant to deformation and chemicalleaching. The container 102 may be generally hollow so as to directlycontain antiseptic solution or to contain an ampoule, pouch, or the likethat stores antiseptic solution. Any of the antiseptic solutionreleasing mechanisms of the related art applicators that allow thesolution to flow from the container 102 into the chamber of the headportion may be implemented in the applicator of the instant invention.This may include devices that puncture an ampoule, tear a pouch, lift aplug, or otherwise provide a fluid pathway for antiseptic solution toflow into the chamber of the head portion. In the variation shown inFIG. 2, the antiseptic solution releasing mechanism includes actuatingarm 106, which may be squeezed toward the fluid container 102 topuncture or break an ampoule having antiseptic solution containedtherein.

The present invention also provides for methods of using the antisepticsolutions and/or applicators as described herein. According to someaspects, the antiseptic solutions and/or applicators of the presentinvention may be used for disinfecting a surface. Preferably, theantiseptic solutions and/or applicators of the present invention may beused for disinfecting a surface prior to a medical procedure, forexample, by applying the antiseptic solution to a patient's skin to killmicroorganisms prior to performing the medical procedure. The patientmay be an animal or a human.

The present invention is further described by way of the followingnon-limiting examples that are given for illustrative purposes only.

EXAMPLES Example 1: Effect of pH on pH-Dependent Antimicrobial AgentDegradation

In this example, the impact of an antiseptic solution's pH on thedegradation rate of a pH-dependent antimicrobial agent, chlorhexidinegluconate, was investigated.

A bulk antiseptic solution containing 2% w/v chlorhexidine gluconate in70% v/v isopropyl alcohol and having an apparent pH of 7.6 was firstdivided into four separate fractions. Each of the first three fractionswas adjusted to an apparent pH of around 4.5 using acetic acid, citricacid, and hydrochloric acid, respectively. One fraction was used as acontrol.

The four fractions were then sealed within four separate glass ampoules.Next, each of the glass ampoules was heated at about 110° C. for about30 minutes using an oil bath, and then cooled. After cooling to roomtemperature, each of the fractions was measured for total relatedsubstances (TRS) using a validated analytical test method. The formationof total related substances indicates degradation of the pH-dependentantimicrobial agent.

Table 1 shows the change in total related substances (ΔTRS) for each ofthe fractions after heating, along with the percentage of degradationrelative to the control.

TABLE 1 % Degradation Relative to Solution Apparent pH ΔTRS ControlAcetic Acid 4.49   0.59% 29% Citric Acid 4.45   0.27% 13% HCl 4.60 ~0.4% 21% Control 7.58   2.05% N/A

As shown in Table 1, the fractions whose pH were lowered with aceticacid, citric acid, or hydrochloric acid showed a substantially lowerchange in total related substances compared to the control fraction,indicating that these fractions provide a lower pH-dependentantimicrobial degradation rate than the control fraction.

Example 2: Effect of pH on pH-Dependent Antimicrobial Agent Degradation

In this example, the impact of an antiseptic solution's pH on thedegradation rate of about 2% w/v chlorhexidine gluconate in 70% v/visopropyl alcohol (having an initial apparent pH of 7.6) wasinvestigated.

A bulk antiseptic solution was first divided into ten separatefractions. The pH of nine of the fractions was adjusted using apH-lowering agent (either gluconic acid, acetic acid, or citric acid),as shown in Table 2. One fraction was used as a control.

TABLE 2 pH lowering Fraction agent pH 1 Gluconic Acid 4.8 2 GluconicAcid 5.5 3 Gluconic Acid 6.5 4 Acetic Acid 4.5 5 Acetic Acid 5.3 6Acetic Acid 5.8 7 Citric Acid 4.5 8 Citric Acid 5.3 9 Citric Acid 5.8 10Control 7.3

The ten fractions were then sealed within separate glass ampoules. Next,each of the glass ampoules was heated at about 115° C. for about 20minutes, and the fractions were then tested for total relatedsubstances. Each of the glass ampoules was then heated at about 115° C.for an additional 20 minutes (40 minutes total), and then again testedfor total related substances. The results of this test are shown inFIGS. 4-6.

For example, FIG. 4 shows the correlation between pH and concentrationof total related substances after 20 minutes and 40 minutes of heatingat about 115° C. As noted in Example 1, the formation of total relatedsubstances indicates degradation of the pH-dependent antimicrobialagent. As shown in FIG. 4, a substantially lower concentration of totalrelated substances (and thus, degradation rate) was observed for thefractions having pH values at or below about 5.5, both after 20 minutesand 40 minutes of heating. FIGS. 5 and 6 show similar trends forfractions whose pH was adjusted using acetic acid and citric acid,respectively. Moreover, none of solutions 1-9 showed related substancesthat were not also present in the control solution.

Example 3: Neutralizing a pH-Lowering Agent in an Antiseptic Solution

In this example, four antiseptic solutions were prepared. Each solutioncontained about 2% w/v chlorhexidine gluconate in 70% v/v isopropylalcohol. The pH of each solution was adjusted to a pH of about 4.5 usinga pH-lowering agent.

The samples were then subjected to a foam pledget either with or withouta neutralizing agent (sodium bicarbonate) embedded therein.Specifically, Solution 1 was passed through a pledget without theneutralizing agent, Solution 2 was not subjected to a pledget, Solution3 was passed through a pledget embedded with the neutralizing agent, andSolution 4 was aggressively stirred/soaked in a pledget embedded withthe neutralizing agent.

After the treatment with the foam pledgets, the pH of the solutions wasmeasured, as shown in Table 3 below:

TABLE 3 Solution pH 1 4.5 2 4.5 3 6.0 4 6.0

As shown in Table 3, the solutions subjected to a foam pledget embeddedwith the neutralizing agent (Solution 3 and 4) showed a substantiallyhigher pH than the solutions which were subjected to a foam pledgetwithout the neutralizing agent (Solution 1) and not subjected to a foampledget (Solution 2).

After the treatment, the concentration of chlorhexidine gluconate andtotal related substances was also measured for each solution. As shownin Table 4, neutralization using the neutralizing agent did notsubstantially impact the chlorhexidine gluconate (CHG) concentration ortotal related substances (TRS) concentration. Moreover, the use of theneutralizing agent did not result in the formation of any additionalimpurities that were not present in the solutions that were notsubjected to the neutralizing agent.

TABLE 4 CHG TRS Solution (% w/v) (% w/v) 1 1.95 1.14 2 1.96 1.25 3 1.981.26 4 1.88 1.27

Example 4: Scavenging a pH-Lowering Agent in an Antiseptic Solution

In this example, a bulk antiseptic solution containing 2% w/vchlorhexidine gluconate in 70% v/v isopropyl alcohol was adjusted to anapparent pH of around 4.5 using a pH-lowering agent. Then, the solutionwas divided into separate fractions.

Three of the fractions were passed over a scavenging agent comprising anion-exchange polymer (specifically, Dowex® 66 free base anion exchangeresin). One fraction was not subjected to the scavenging agent and wasused as a control.

The first three fractions were pooled, and the pH of the solutioncontaining the pooled fractions was determined to be 5.7. Furtheranalysis of the chemical characteristics of the antiseptic solutionsusing a validated test method was then performed, specifically tomeasure the concentration of chlorhexidine gluconate (CHG) in the pooledsolution and the control solution. The results of this analysis areshown in FIG. 7 and Table 5.

In particular, FIG. 7 shows that scavenging the pH-lowering agent usingDowEx beads resulted in minimal impact to the chlorhexidine gluconatecontent (<8%). Table 5 shows that scavenging the pH-lowering agent usingDowEx beads did not substantially impact the concentration of totalrelated substances (TRS).

TABLE 5 TRS Solution (% w/v) Pooled 1.82 Control 1.96

Moreover, scavenging the pH-lowering agent using DowEx beads did notresult in the formation of any additional impurities that were notpresent in the control solution.

The same experiment was also performed using a different ion-exchangepolymer (specifically, AMBERLITE™ IRA96 anion exchange resin) as ascavenging agent.

In this experiment, the pH of the solution containing the pooledfractions was determined to be 6.2. Further analysis of the chemicalcharacteristics of the antiseptic solutions using a validated testmethod was then performed, specifically to measure the concentration ofchlorhexidine gluconate (CHG) in the pooled solution and the controlsolution. The results of this analysis are shown in FIG. 8 and Table 6.

In particular, FIG. 8 shows that scavenging the pH-lowering agent usingAmberlite beads resulted in minimal impact to the chlorhexidinegluconate content. Table 6 shows that scavenging the pH-lowering agentusing Amberlite beads also resulted in minimal impact to theconcentration of total related substances (TRS).

TABLE 6 TRS Solution (% w/v) Pooled 1.56 Control 1.96

Moreover, scavenging the pH-lowering agent using Amberlite beads did notresult in the formation of any additional impurities that were notpresent in the control solution.

The same experiment was then repeated using a different ion-exchangepolymer (specifically, Amberlyst® A21 free base anion exchange resin) asa scavenging agent.

In this experiment, the pH of the solution containing the pooledfractions was determined to be 9.3. Further analysis of the chemicalcharacteristics of the antiseptic solutions using a validated testmethod was then performed, specifically to measure the concentration ofchlorhexidine gluconate (CHG) in the pooled solution and the controlsolution. The results of this analysis are shown in FIG. 9 and Table 7.

In particular, FIG. 9 shows that scavenging the pH-lowering agent usingAmberlyst beads resulted in minimal impact to the chlorhexidinegluconate content. Table 7 shows that scavenging the pH-lowering agentusing Amberlyst beads also resulted in no impact to the concentration oftotal related substances (TRS).

TABLE 5 TRS Solution (% w/v) Pooled 1.96 Control 1.96

Moreover, scavenging the pH-lowering agent using Amberlyst beads did notresult in the formation of any additional impurities that were notpresent in the control solution.

Example 5: Antimicrobial Effect of Antiseptic Solutions

In this example, the impact of an antiseptic solution's pH onmicrobiological efficacy of a pH-dependent antimicrobial agent,chlorhexidine gluconate, was investigated.

A bulk antiseptic solution containing 2% w/v chlorhexidine gluconate in70% v/v isopropyl alcohol was first divided into six separate fractions.These six fractions were individually modified as follows:

Final Fraction Modification Test pH 1 pH-lowering agent (gaseous carbonOperative dioxide) added, then released range 2 Acidified withpH-lowering agent Operative (trifluoroacetic acid) and subjected torange neutralization with neutralizing agent (sodium bicarbonate) 3Acidified with pH-lowering agent Operative (trifluoroacetic acid) andsubjected to range scavenging agent (DowEx resin) 4 Acidified withpH-lowering agent Operative (trifluoroacetic acid) and subjected torange scavenging agent (Amberlyst resin) 5 Acidified with pH-loweringagent 4.5 (trifluoroacetic acid) to a pH of about 4.5 6 None (ControlFraction) Operative range

All six fractions were then tested against Staphylococcus aureus ATCC29213 at 100%, 10%, and 0.01% of the use concentration for chlorhexidinegluconate (i.e., three different test concentration samples for each ofthe six fractions, totaling 18 samples). The average log reduction ofthe bacteria was recorded after 30 seconds for the 100% and 10% samples,and after 15 minutes for the 0.01% samples. The results of the study areshown in FIG. 10.

In particular, FIG. 10 shows that, as expected, total kill of thebacteria was observed for all formulations at the 100% testconcentration. However, at the 10% test concentration, Fraction 5 (i.e.,the fraction whose pH was 4.5, or below the operative pH range) showed alower average log reduction compared to the other fractions (i.e., thefractions whose pH were within the operative range). In general, nosubstantial difference was observed in the average log reduction for theother five formulations.

The results of this study indicate that a pH-dependent antimicrobialagent provided in a solution with a pH that is below the operative pHrange (e.g., a pH of about 4.5) shows less than acceptablemicrobiological activity, as evidenced by the lower log reduction ofFraction 5 compared to the other five fractions. Moreover, no change inthe microbiological efficacy was observed for antiseptic solutionssubjected to carbon dioxide, acidified and subsequently neutralized, oracidified and subjected to scavenging compounds.

1. An antiseptic comprising: a solution comprising a pH-dependentantimicrobial agent, the pH-dependent antimicrobial agent having anoperative pH range, wherein the solution has a pH on storage that islower than the operative pH range.
 2. The antiseptic of claim 1, whereinthe pH-dependent antimicrobial agent comprises chlorhexidine and/or asalt thereof.
 3. The antiseptic of claim 1, wherein the pH on storage isat least about 0.5 units lower than the operative pH range.
 4. Theantiseptic of claim 1, wherein the pH on storage is lower than about 5.5. The antiseptic of claim 1, wherein the solution is provided in anapplicator configured to apply the solution to a surface.
 6. Anantiseptic comprising: a solution comprising a pH-dependentantimicrobial agent, the pH-dependent antimicrobial agent having anoperative pH range, wherein the solution has a first pH on storage and asecond pH upon activation, wherein the first pH is lower than theoperative pH range, and the second pH is within the operative pH range.7. The antiseptic of claim 6, wherein the pH-dependent antimicrobialagent comprises chlorhexidine and/or a salt thereof.
 8. The antisepticof claim 6, wherein the operative pH range is about 5.5 and above. 9.The antiseptic of claim 6, wherein the first pH is lower than about 5.10. The antiseptic of claim 6, wherein the solution further comprises apH-lowering agent.
 11. The antiseptic of claim 10, wherein at least aportion of the pH-lowering agent is released from the solution uponactivation.
 12. The antiseptic of claim 10, wherein the pH-loweringagent reversibly reacts with at least one component in the solution toform an acid.
 13. The antiseptic of claim 10, wherein the pH-loweringagent is gaseous carbon dioxide.
 14. The antiseptic of claim 10, whereinthe pH-lowering agent comprises an acid.
 15. The antiseptic of claim 14,wherein the solution is provided in an applicator configured to applythe solution to a surface, wherein the applicator comprises anapplication member, the application member including an interactionagent, wherein the interaction agent interacts with the pH-loweringagent upon activation to raise the pH of the solution to within theoperative pH range.
 16. The antiseptic of claim of claim 15, wherein theinteraction agent comprises a scavenging agent, wherein the scavengingagent removes at least a portion of the pH-lowering agent from thesolution.
 17. The antiseptic of claim of claim 15, wherein theinteraction agent comprises a neutralizing agent.
 18. The antiseptic ofclaim 14, wherein the solution is provided in an applicator configuredto apply the solution to a surface, wherein the applicator comprises apledget, the pledget including an interaction agent, wherein theinteraction agent interacts with the pH-lowering agent upon activationto raise the pH of the solution to within the operative pH range.
 19. Amethod of decontaminating a surface comprising: providing a solutioncomprising a pH-dependent antimicrobial agent, the pH-dependentantimicrobial agent having an operative pH range, and a first pH that isless than the operative pH range, and applying the solution to asurface, wherein the solution has a second pH upon activation that iswithin the operative pH range.